Internet Protocol version 6 (IPv6) is the next-generation internetworking protocol version designated as the successor to IPv4. IPv4 is the first implementation used in the Internet and is still widely used. These protocols are used as an Internet Layer protocol for packet-switched internetworks.
There a class of messages used in the IPv6 protocol known as “Neighbor Discovery” messages. Examples of Neighbor Discovery messages are Router Solicitation, Router Advertisement, Neighbor Solicitation, and Neighbor Advertisement messages. These messages enable nodes to communicate on an IPv6 link, discover routers, resolve layer-2 addresses, and to perform other related functions.
The IPv6 protocol supports stateless auto-configuration, whereby a node can generate a 128-bit address, by itself, based on the first 64-bits (prefix), present in a Router Advertisement message sent by the IPv6 router on the link. Consequently, a node need not send a request to a dynamic host configuration protocol (DHCP) server for an address. On the other hand, in some network environments a network router may be configured to perform neighbor discovery functions using (stateful) DHCPv6 techniques.
The network address generation feature of IPv6 presents certain challenges to avoid address IPv6 address conflicts when a wireless client device roams from a wireless access point device that hosts one virtual local area network to a wireless access point that hosts another virtual local area network.